32P-postlabelling analysis of human tissues and its potential use for biomonitoring

Samples of clinically normal oral tissue were obtained from 17 tobacco smokers and 7 non- or ex-smokers undergoing surgery for intra-oral squamous cell carcinoma. Isolated DNA was analysed for the presence of aromatic DNA adducts using the 32P-postlabelling technique with adduct enhancement by either butanol extraction or nuclease P1 enrichment. DNA adduction detected following butanol extraction was more diverse and at a higher level than obtained with the P1 method. Adduct levels in the smokers and non- or ex-smokers were 1163 +/- 375 and 774 +/- 318 amol/micrograms, respectively. This difference is statistically significant (p < 0.05). The differential enhancement of adducts with the two protocols suggested that arylamines may be the source of at least a proportion of the DNA adduction detected. These data indicate that oral tissues are likely to be a suitable source of material for human biomonitoring and furthermore they highlight the importance of utilizing more than one enhancement procedure when examining DNA adduction induced by complex mixtures such as tobacco smoke or those encountered at industrial plants.